130 JOURNAL ELISHA MITCHELL SCIENTIFIC SOCIETY. 



gradually develop nuaierous yolk globules which darken their appearance, pass- 

 ing through the receptaculum tieminis are fertilized, and entering the uterus seg- 

 mentation begins, finally the mass of developing eggs in the genital tubes rup- 

 tures them and the eggs and embryos are set free within the body of the cyst. 



PLATE V. Structural effects of the disease in roots of cotton and peach. 



Fig. 29. Cross section of gall on lateral root of cotton plant; a, female cyst 

 showing ovaries, etc. ; b, old female cyst showing eggs and young larva? in the 

 amorphic remains of the parent ; c, deformed vascular tissue by the side of a 

 cyst; cl, deformed vascular tissue, the tubes turned iu a radial and tangential 

 direction to the axis of the root ; e, liber fascicle in normal position of healthy 

 root: e', liber fascicle displaced, and, by increased growth of parenchyma and 

 vascular tissue, carried far out from normal position ; e", liber fascicle deformed 

 and growing in a radial direction ; e'", liber fascicle displaced and growing iu a 

 tangential direction. 



Fig. 30. Cross section of healthy lateral root of cotton plant magnitied, but iu 

 proportion with Fig. 29, 



Fig. 31. Galls on lateral root of cotton plant (natural size). 



Fig. 32. Root-gall of peach, natural size, but small specimens. 



Fig. 33. Section through female cyst in root of peach, showing the ultimate 

 growth of soft, pseudo-parenchymatous tissue which sometimes entirely fills the 

 cavit}' before the larvae have all escaped ; a, amorphic remains of female cyst, 

 showing eggs and part of genital tubes ; b, original outline of cyat ; c, hypertro- 

 phied tissue from surface of cavity of cyst. 



PLATE VI. Female cysts and structural effects of the disease in roots of the 

 tomato, and the tubers of the potato (excepting Figs. 42 — 47). All magnified. 



Fig. 34. Mature female cyst ; a, exsertile spear ; b, middle part of oesophagus ; 

 c, ovary ; d, eggs escaped from the uterus. 



Fig. 35. Mature female cyst of a different form. 



Fig. 36. Cross section of diseased root of tomato ; a and b, female cysts ; c, 

 dead cysts which probably failed to be fertilized. 



Fig. 37. Section still more magnified ; a, cyst cavit}' of female showing eggs 

 and larviB iu amorphic remains of the parent ; b, normal vascular tissue iu cross 

 section ; c, deformed vascular tissue turned in a radial and tangential direction 

 around the cyst. 



Fig. 38, Section of outer portion of potato tuber showing a, female cyst exter- 

 nal with head end only in the tissues ; b, radial elongation of cells. 



Fig. 39. Sexually immature larvae making its way through cells of the potato 

 tuber. 



Fig. 40. Section of outer portion of potato ; a, young cyst m situ ; b, cork cells 

 of lenticel (the section was through the side of a lenticel). 



Fig. 41. Section of outer portion of potato tuber where decay of the tissues 

 has begun ; a, female cyts in situ; 6, cyst cavity containing amorphic remains of 

 parent, and young larv;e and eggs. 



Fig. 42. Es:g of 46; 43, cell division of same in process of development; 44, 

 young larva in egg membrane ; 45, young larva after hatching ; 46, mature gravid 

 female ; a, mature egg ; b, young ovum (Figs. 42 — 46 illustrate the egg, larva and 

 mature female of the nemitoie, wliieh produces the disease of the Irlsb potato 

 characterized by Prof. Scribner). 



Fig. 47. Mature femxle of a different genus found so:netimes associated with 

 the former. 



n 



